It was developed by the W3C's Efficient Extensible Interchange Working Group and is one of the most prominent efforts to encode XML documents in a binary data format, rather than plain text.
Using EXI format reduces the verbosity of XML documents as well as the cost of parsing.
Improvements in the performance of writing (generating) content depends on the speed of the medium being written to, the methods and quality of actual implementations.
EXI is useful for The World Wide Web Consortium (W3C) formed a working group to standardize on a format in March 2006.
EXI was chosen as W3C's Binary XML format after an evaluation of various proposals that included Fast Infoset.